1. Field of the Invention
The present invention relates to aqueous compositions containing oxadiazolinones and polyamines, which cure at elevated temperatures to form cross-linked polymers coatings, adhesives and sealants.
2. Description of the Prior Art
Both one-component and two-component aqueous compositions are known. Examples include aqueous polyurethane dispersions and aqueous polymer emulsions and dispersions. They can be dried to form coatings and can under certain circumstances, e.g., with the addition of cross-linking hardeners, also cure to form water resistant and solvent resistant coatings. All of the known aqueous compositions of this type either have the disadvantage of a limited pot life when a cross-linking agent has been added, or have the disadvantage of releasing organic components contained within the cross-linking agent. For example, the blocking agent is liberated from blocked polyisocyanates during the cross-linking reaction. With regard to etherified melamine formaldehyde resins, which are also used on a large scale industrially, monoalcohols, among others, are released during cure.
A large number of commercial PUR dispersions contain tertiary amines or ammonia as neutralizing agents, which escape from the film as it dries or cures. This may result in pores forming as a film defect, and may cause give off an odor.
An object of the present invention is to avoid these disadvantages and provide aqueous, two-component cross-linkable compositions, which are stable at ambient temperatures of approximately 20 to 30.degree. C. and which may be cross-linked at elevated temperatures to form a film without giving off volatile organic constituents from the film.
These objects may be achieved with the aqueous compositions containing oxadiazolinone derivatives and polyamines described hereinafter.